Other Income (Loss), Net (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Income And Expenses [Abstract]
Gain on fair value of prior equity interests											$ 51,668
Gain (loss) on sales/distributions of ownership interests									5,158	(4,032)	5,260
Realized gains on sales of marketable securities									269	23	1,552
Other										(93)	(656)
Total other income (loss) for parent company									5,427	(4,102)	57,824
Total other loss for consolidated businesses									(127)	(108)	(4)
Total other income (loss), net	$ 4,280	$ 83	$ 637	$ 300	$ (4,032)	$ (68)	$ (46)	$ (64)	$ 5,300	$ (4,210)	$ 57,820